Here's a cool site if you want to have a custom license plate frame made for your BS, or other cycle (they offer frames for cars, as well, and other products):
http://www.betadesigns.com/products/Under "Products" select "Custom m/c license plate frames", and follow instructions to "build" your frame. I just ordered one for my Kawasaki 900, and will order one soon for my in-progress GTR. They have quick turn-around, free U.S. shipping, and reasonble prices. Will post photo when the frame arrives.
Ken